Introduction: Langerhans cell histiocytosis (LCH) is a very rare disorder, and usually considered a disease of childhood. It is rarely observed in adults. Its etiopathogenesis remains to be elucidated. One possible etiological cause is a reactive proliferation of Langerhans cells following chemotherapy or radiotherapy for Hodgkin's disease (HD). Eosinophilic granuloma is the benign accumulation of histiocytes located primarily in the bones, but which also affects other organs, including the skin, lungs and lymph nodes. The time interval between LCH occurrence and previous lymphoma is variable. The occurrence of eosinophilic granuloma in a patient with Hodgkin disease has rarely been reported. Objective: This case report aimed to describe the clinic-pathological, histopathological, immunohistochemical and other features of LCH and to analyze LCH clinical features for improving diagnosis and decreasing misdiagnosis rate. Case report: In this report, a 38-year-old female presented with LCH twenty-two months after diagnosis and treatment of nodular sclerosing HD. The patient presented with generalized lymphadenopathy and general weakness. The Langerhans cells diffusely infiltrated in the inguinal lymph node and the tumor cells were positive for CD1a and S-100 expression. The patient received chemotherapy and show complete remission. Conclusion: LCH has a very rare occurrence following HD in adult. The definitive diagnosis depends on pathological biopsy and immunohistochemistry. Although specific therapeutic approach hasn't been well established, combined chemotherapy for multisystem lesions and surgical operation or radiotherapy for unifocal lesions may improve the therapy.